speed for sale just came out with a set of gt28r twins for supras capible of making power of 550+ hp. looking over the setup of them, it looks alot like our stock twins. any gurus think this could be a good idea if a custom manifold could be fabricated?

http://www.speedforsale.com/suprapar...roducts_id=553

 

Rx7store.net did a twin gt28r for this guy:

http://www.rx7store.net/category_s/339.htm

When I inquired about doing either a gt35r or twin 28r's they were all over the gt35r saying it spooled awesome all that.

What they said about the twin gt28r setup, well the only thing they said was "we do not do the twin gt28r anymore, it is not worth it", not really sure what they meant, but yeah.

 

badass, ive always wanted to make some sequential ball bearing turbo's looks like somone has already done it.

 

I just dug up the old thread that Jason started about this, posted about 3 years ago, on the last page he said that it wasnt worth it because going single was cheaper.

https://www.rx7club.com/single-turbo-rx-7s-23/twin-gt28r-turbo-kit-pics-387757/

And heres one from 2004

https://www.rx7club.com/single-turbo-rx-7s-23/building-independent-twin-gt28r-gt28rs-kits-373529/page2/

also, I just found this one, its an rx8 with the twin gt28r's

http://www.mazda.com.mx/MusaWeb/disp...ofile49&bhcp=1

 

those arent sequential though, i could see how parallel turbo's might not be worth the price above single, but sequential, you cant argue with the powerband.

 

anything making over 400hp with instant spool is worth it IMO. is rather expensive though

 

ohh I didnt realize the ones from your original link for the supra are sequential, sorry about that.

If so, then that would be sick if they could be modified to fit an FD.

 

maybe contact them see if they would be interested in making a kit like that for the fd..i know alot of guys would prob interested in that. if i got back in the FD scene i would prob be interested.

 

it really only looks like it would need a manifold to work

 

Um....

Guys, why go through all the trouble of trying to make supra twin's work on an RX-7??? If I remember correctly Bryan's turbo's (BNR's) are on par with a twin GT28 setup, are fully functional with 7's and can make 400+ in sequential mode (I made the equiv of 383 (American) whp when I installed and tuned mine to 1.1bar, on an UNPORTED Engine).

Support the BNR's correctly and run Sequential, you'll surprise the crap out of a LOT of car's...

 

The BNR stage 3's are twin gt28 CHRAs with something custom from garrett to retain use of the stock FD oil system and coolant lines going to the turbos.

 

Yup, this is true, but I wasn't going to say it outright like that. I only know of one time when Bryan has come out and said that, I was under the impression it was a bit of a secret

 

I am fairly certain he has the market cornered. knowing that he uses a high quality chra should help him sell more. plus, he knows what it takes to make them bolt up to OE equipment and knows how to do it all under 2400 bucks. I doubt any of the big names will ever be able to compete with that.

Plus, after speaking with Bryan on the phone, I have already decided that the BNR stage 3's are the route that I am going.

So for those that want twin GT28's, and want sequential. Go with the BNR Stage 3's.

No muss, no fuss, and all awesomeness.

 

A couple things to keep in mind when you plan your build for them: They run HOT when operating at above standard levels (say 1 bar), I'd make sure you've got adequate cooling (my GReddy SMIC doesn't quiet cut it, getting a V-Mount next month) and/or Water Injection. Also I'd suggest planning to get upgraded Solenoids, since the BNR's really start to perform at +15psi, and the old, stock solenoids can't really hang at that level for long..

So yeah, cooling capable of handling a single, water injection and upgraded Solenoids are three things you may not think of for BNR's, but I have learned are necessary if you really want to get the most out of them.

 

Great point about the solenoids!

I have already began acquiring parts for the other two, however, I had not given thought to the idea of IF I wanted to run above 15 psi.

I suppose I should upgrade solenoids Just in case I decide to up the boost.

Any suggestions?

 

Axiom makes a kit, you can speak to saxyman990 on here about them. I'm actually guilty of running boost above the stock solenoids w/o upgrading... I'm getting there though, lol. Also make sure you've got new (viton) check-valves, as the originals can stick and clog.

ANOTHER thing, make sure you upgrade the MAP sensor... GM makes one that will require modifying your PFC map to read, Apexi makes one which is plug and play.. that way you won't be tuning blind above 16psi.

 

thats cool, i never knew that the bnr's are gt28's, still journal bearing though right, i wish they were gt28r's

 

Would be very nice if the BNR's had ball bearing middles!

 

it wouldn't make an appreciable difference. BNRs perform about the same as stock twins, both sequentially and parallel.

 

I love the BNR's but the problem is the rear housing... Its a stock rear housing machined to accept the new CHRA which means it is way restrictive..... Stock gt28 are rated for 310hp matching them together should put you with a capability of around 600... BNR's can never hit this mark because of the tiny rear housing... As well a lot of times when you run BNR's seq. at high boost you have to raise your transition a little so that the turbo can completely spool up...If they were full ball bearing you could probalby make more power at a lower RPM... Although the BNR's are far superior to the stock and 99 spec turbos if somehow someone was to biuld a complete gt28r with larger rear housing seq system it would way outperform the BNR's but casting housing is expensive so they probably wouldnt be at the 2400 mark like the BNR. I do have a feeling though that if they were produced there would be a lot of guys throwing there singles in the garbage...

Chris

 

The problem with the BNRs or virtually any other stock twin based setup is the stock manifold. So long as you're stuck with the stock sequential manifold, it'll be limited.

 

Yup... It's too bad really..

 

I agree, how good would it be to have aftermarket sequential manifolds...

 

I would love to see someone produce a tubular style manifold that could house the twins and still have them work sequentially!

 

I think a tubular manifold would be so complicated it wouldnt yield much.